This invention relates to a method and apparatus for automatically determining somatic state of a human subject, and more particularly to quantifying the somatic state of the human subject to which the apparatus is connected.
There is a continuing demand in the field of human psychology for means whereby the somatic state of subjects can be quantified. A subject's somatic state is the mental state due to such things as the subject's emotions (e.g., joy, anger, happiness, sadness, elation, surprise, disgust or fear), level of mental activity (e.g., as a result of doing mental arithmetic or writing a poem) or motor activity (e.g., moving a hand or foot). Heretofore, psychologists have had to rely on interviews with the subject to elicit information about the subject's somatic state. Questions posed to the subject result in answers that require interpretation based on subjective criteria, and the results achieved by such methods are at best relative.
Somatic states tend to be associated with responses in a number of visceral organs (e.g., the heart, stomach and intestines). However, the particular combination of visceral responses that makes a particular stimulus or state "somatic" is not precisely defined. Similar combinations of visceral responses can be indicative of widely different somatic states. In addition to interviewing the subject, conventionally, psychologists also use electroencephalographic ("EEG") waveforms to interpret the subject's mental state. This too introduces subjective criteria into the analysis because a human expert is required to interpret the EEG waveforms.
Recently, neural networks have come to be used as tools to monitor drug-specific EEG power spectra patterns during the administration of drugs, as shown, for example, by Veselis et al., "Analytical Methods to Differentiate Similar Electrographic Spectra: Neural Network and Discrinminant Analysis," 9 Jounal of Clinical Monitoring 257 (September 1993).
In view of the foregoing, it would be desirable to be able to provide a method and apparatus for automatically determining somatic state, and more particularly to quantifying the somatic state of a human subject to which the apparatus is connected.